1. What do we know about L~Ledd accretion – BHB, ULX –
Chris Done,
ISAS/JAXA and University of Durham

2. Interacting Binaries - BRIGHT High mass XRB & low mass XRB
Wind accretion – Messy
High mass companion star
Roche lobe overflow= cleaner
All low mass are Roche lobe, but a few high mass are also

3. Variable variability!
Roche lobe accretion onto black hole or low B field NS can vary dramatically, or vary a bit, or be constant!
Hydrogen ionisation instability (Osaka, Smak, Lasota)
4U m=1.4 d=3
4U m=1.4 d=7.4
2 years

4. Roche lobe geometry
Black hole
Neutron star – mass is 1.4 not 10M so binary much smaller for given companion star
More NS constant, most BHB do transient outbursts
Neutron star

5. As seen in most BH in our galaxy
J. Orosz
Transient - outer disc kT < 4000K (H ionisation)
Small Mdot and/or large outer radius
Persistent – need large mdot and/or small

6. Disc instabilities –H ionisation
Steady state has dM/dt = constant at all radii
Then balance heating=cooling at each radius
Heating from gravity via viscosity. Cooling from radiation diffusing out from disc (depends on optical depth)
Hydrogen ionisation instability as cooling no longer efficient

7. Dubus et al 2001

8. Disc instabilities – predicts transient behaviour
Coriat et al 2012

9. Disc instabilities –H ionisation
Also sets peak luminosity
Mdisc - integrate surface density just before outburst
Smax ~ 150 R g/cm2
(10 Msun, a=0.02)
Mdisc=50 Rd3 g
Falls in on viscous time at Rd
tvisc= tdyn / [alpha (H/R)2 ]
L=h Mdot c2 = h Mdisc c2/tvisc
Proportional to Rd1.5
Big discs do high Lpeak

11. Black hole binaries
Observe dramatic changes in SED with mass accretion rate onto black hole
Dramatic changes in continuum – single object, different days
Underlying pattern in all systems
High L/LEdd: soft spectrum, peaks at kTmax often disc-like, plus tail
Lower L/LEdd: hard spectrum, peaks at high energies, not like a disc (McClintock & Remillard 2006)

12. Hardness – intensity diagram
But not at fixed luminosity like the models say!
Outburst starts hard, source stays hard as source brightens
Makes transition to disc dominated via come complex spectra
Then returns to hard state at lower luminosity
Fender Belloni & Gallo 2004

13. Jet evolution in BHB outburst
The disc models assumed that the emission thermalised. That’s not necessarily true at low L/Ledd where the flow is not very dense. If its not thermalising then its not cooling as efficiently so the flow heats up. This can lead to a hot, optically thin, geometrically thick inner flow replacing the inner disc. The hot electrons in this flow can compton upscatter any low energy photons from a residual outer disc, but there are not many of these, so the spectrum is hard
Fender Belloni Gallo 2003

14. Peak low/hard state: lowish kT
Optically thick, tau=1.5, kT=30 keV GX339-4 Motta et al 2009

15. Peak low/hard state: lowish kT
kT=15 keV! GRS1739 Miller et al 2012.
Yabu, Done et al 2017

16. Moving disc – moving QPO
Energy spectra: disc moves 50-6ish Rg as make transition
Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant!
Large radius moves, Small radii constant

17. Mass from QPO Can scale ONLY if looking at same type of QPO!!!
See QPO in NGC5408 at 10mHz
See similar freq in GRS !! Middleton et al 2011

18. Moving disc – moving QPO
Energy spectra: disc moves 50-6ish Rg as make transition
Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant!
Large radius moves, Small radii constant

19. Variability of disc
L/LEdd AT4max (Ebisawa et al 1993; Kubota et al 1999; 2001)
Constant size scale – last stable orbit!! BH spin

20. Disc spectra: last stable orbit
L/LEdd T4max Ebisawa et al 1993; Kubota et al 1999; 2001
Constant size scale – last stable orbit!!
Not quite as simple as this
BHSPEC - Proper relativistic emissivity (Novikov-Thorne)
corrections for spectrum not being blackbody (fcol)
Corrections for relativistic propagation effects Davis et al 2005
Kolehmainen & Done 2010

21. Relativistic effects
Relativistic effects (special and general) affect all emission (Cunningham 1975)
Emission from the side of the disc coming towards us is blueshifted and boosted by Doppler effects, while opposite side is redshifted and suppressed.
Also time dilation and gravitational redshift
Broadens spectrum at a give radius from a narrow blackbody
flux
Another area where Astro e2 will give major progress in an independent test of the accretion flow models. The accretion disc moves fast in a strong gravitational field, so both special and general relativistic effects modify its spectrum. Doppler shifts and length contraction mean that the emission from the disc moving towards us is blueshifted and boosted, while that moving away is redshifted and suppressed. Then time dilation and gravitational redshift drag everything redwards. The strength of these all effects decrease with radius. All emission from the disc is affected, but its much easier to see on intrinsically narrow features – lines. X-ray illumination of the disc gives iron Kalpha line. Moving inner disc models predict broader line in softer spectra. But the measured line profile can be distorted by narrow absorption features superimposed on the emission. The high spectral resolution of Astro e2 will unambiguously show these, enabling the intrinsic line profile to be measured.
Energy (keV)
Fabian et al. 1989

22. Theoretical disc spectra
Surely even disc spectra aren’t this simple!!!!
Disc annuli not blackbody – too hot, so little true opacity. Compton scattering important.
Modified blackbody Shakura & Sunyaev 1973
Describe by colour temperature fcol
And relativistic smearing effects on the spectra at each radius
kTeff
fcol kT
Log n f(n)
Log n

23. These make a (bit) of difference
Fully relativistic energy generation and ray tracing and full radiative transfer (bhspec)
Sum of blackbodies (diskbb)
XMM-Newton data from LMC X-3
Peaks at 3.5 keV for 10 solar mass L~LEdd
Peaks 0.035keV=30eV for 1e9 solar mass L~LEdd

24. BHB Disc spectra:10 M L/LEdd ~1
Kolehmainen et al 2013
LMC X-3
Peak at 3.5 keV for ~0.8LEdd
3.5 x (10/107)1/4~0.1keV for 107 AGN (Ross, Fabian & Mineshige 1991)
‘broadened disc’

25. Moving disc – moving QPO
Energy spectra: disc moves 50-6ish Rg as make transition
Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant!
Large radius moves, Small radii constant

26. BHB steep power law spectra
GX339-4 compare disc and VHS (plateau in GRS1915)
Lower temp for similar luminosity
See disc is truncated slightly in VHS as seen by QPO
Kubota & Done 2016

27. Disk + Compton! Bandpass!!
All high L states have disc plus tail
Disc – low E, constant on short timescales
Compton – high E, varies on short timescales
Steep power law state is HARD at low E

28. Disk + Compton! Bandpass!!
XTEJ
ASCA-RXTE-OSSE
Steep power law state is HARD at low E
low kTbb~0.6keV, high kTe~20keV compared to ULX

29. GRS (Nh 4-6e22!)
kTe~7keV kTe~3keV
Done et al 2004

30. M31 transient jan 2012
Lmax=1.3e39
Radio flaring correlated with harder tail (VHS)
Middleton et al 2013

31. M31 transient jan 2012 Lmax=5e39 Middleton et al 2011
Bright BHB transients in other galaxies

32. Gladstone Roberts & Done 2008
ULX state ?
Gladstone Roberts & Done 2008

33. Gladstone Roberts & Done 2008
ULX state ?
Gladstone Roberts & Done 2008

34. Luminosity > LEdd ?
Standard disc assumes that energy liberated locally through mass accretion is radiated locally
Not necessarily true – can be carried radially along with the flow is accretion timescale < radiated timescale
Optically thick advection – slim discs (Abramowicz et al 1988) only different L>LEdd
Heats next ring in – but can advect that also. Then lose does the black hole!
L=LEdd log(1+mdot/mdotEdd)
Log n f(n)
Log n

35. Luminosity > LEdd ?
Standard disc assumes that energy liberated locally through mass accretion is radiated locally
Not necessarily true – can be carried radially along with the flow is accretion timescale < radiated timescale
Optically thick advection – slim discs (Abramowicz et al 1988) only different L>LEdd
Heats next ring in – but can advect that also. Then lose does the black hole!
L=LEdd log(1+mdot/mdotEdd)
Log n f(n)
Log n

36. Luminosity > LEdd ?
Standard disc assumes that mdoty constant with R
Not necessarily true – can lose mass in a wind is L>LEdd (Shakura & Sunyaev 1973)
L=LEdd log(1+mdot/mdotEdd) i.e. same as before but for different reason – local flux at disc surface has to be <LEdd
Two possible responses – so disc probably does both as seen in numerical simulations
Log n f(n)
Log n

37. Supereddington RX0439
Jin et al 2017
M=7e6
Mdot though outer disc is 12x Eddington and zero spin
Lobs=4.6LEdd
Losing lots of power!
Winds/advection?
Know mass, so know Mdot through outer disc!!

38. ULX 1313 X-1 vs RXJ0439

39. Supereddington RX0439
Jin et al 2017
M=7e6
Mdot though outer disc is 12x Eddington and zero spin
Lobs=4.6LEdd
Losing lots of power!
Winds/advection?

40. RXJ 0439 vs 1H0707

41. RXJ 0439 vs 1H0707

42. Do we have a clean view - Winds
2e6M a=0, 0.9, 0.998
L/Ledd = 20, (30 degrees)
L/Ledd = 44,
(60 degrees)
Done & Jin 2016
Clean disc??

43. Do we have a clean view - Winds
2e6M a=0, 0.9, 0.998
L/Ledd = 20, (30 degrees)
L/Ledd = 44,
(60 degrees)
Done & Jin 2016
Clean disc??
SUPEREDDINGTON
Strong winds???

44. Wind models for Ka line in 1H0707
Means no need for high spin in radio quiet NLS1
Could go back to high spin=highly relativisitic jet models!! Done & Jin 2016
Hagino et al 2016

45. Conclusions: Disc instability controls long term behaviour
Lpeak<~Ledd
BHB spectral states SUBEDDINGTON
Bandpass makes a difference RXTE (BHB) XMM (ULX)
High L~Ledd can show disc (constant radius)
Or very high state – larger size scale, lower kTe – connects to ULX?
But ULX don’t scale to mildly supereddington AGN
Maybe because they are highly superEddington B field NS